Answer:
i a
i b
i c
iia
iib
\
iic
There is insufficient evidence to conclude that the analyst is right because the population mean fee by the analyst does not fall within the confidence interval
Step-by-step explanation:
From the question we are told that
The sample size is
The sample mean is
The sample standard deviation is
Considering question i
i a
At
given that the confidence level is 95% = 0.95
the level of significance would be
The critical value of from the normal distribution table is
So the sample size is mathematically evaluated as
=>
=>
i b
At and confidence level = 95% => =>
=>
=>
i c
At confidence level = 99% =>
The critical value of from the normal distribution table is
=>
=>
=>
Considering ii
Given that the level of significance is
Then the critical value of from the normal distribution table is
Generally the margin of error is mathematically represented as
substituting values
Generally the 90% confidence interval is mathematically evaluated as
=>
=>
So the interpretation is that there is 90% confidence that the mean fee charged to H&R Block customers last year is in the interval .So there is insufficient evidence to conclude that the analyst is right because the population mean fee by the analyst does not fall within the confidence interval.